Here's my code :

To get the formid, I use a formpicker in the macro.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsl:stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]>
<xsl:stylesheet 
  version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
  xmlns:msxml="urn:schemas-microsoft-com:xslt"
  xmlns:umbraco.library="urn:umbraco.library" xmlns:Exslt.ExsltCommon="urn:Exslt.ExsltCommon" xmlns:Exslt.ExsltDatesAndTimes="urn:Exslt.ExsltDatesAndTimes" xmlns:Exslt.ExsltMath="urn:Exslt.ExsltMath" xmlns:Exslt.ExsltRegularExpressions="urn:Exslt.ExsltRegularExpressions" xmlns:Exslt.ExsltStrings="urn:Exslt.ExsltStrings" xmlns:Exslt.ExsltSets="urn:Exslt.ExsltSets" xmlns:contourpoll="urn:contourpoll" xmlns:umbraco.contour="urn:umbraco.contour" 
  exclude-result-prefixes="msxml umbraco.library Exslt.ExsltCommon Exslt.ExsltDatesAndTimes Exslt.ExsltMath Exslt.ExsltRegularExpressions Exslt.ExsltStrings Exslt.ExsltSets umbraco.contour contourpoll">


<xsl:output method="xml" omit-xml-declaration="yes"/>

<xsl:param name="currentPage"/>

    <xsl:param name="formid" select="/macro//formid" />
    
<xsl:template match="/">
  
    <xsl:if test="$formid">
     <xsl:variable name="records" select="umbraco.contour:GetRecordsFromForm($formid)"/>
     <xsl:variable name="numberOfRecords" select="count($records/uformrecord)" />


    
    
   <div class="results" style="width:200px; margin-left:0px;">
       <h2>Résultats du sondage</h2>
     
     <xsl:for-each select="contourpoll:PossibleAnswers($formid)//question">
    <xsl:variable name="numberOfAnswers" select="count(./answer)" />
       
    <xsl:value-of select="caption"/>
      <ul style="list-style:none;padding-left:0px;margin-left:20px;">
        <xsl:for-each select=".//answer">
      <xsl:sort select="count($records//value [@key = current()/@id])" data-type="number" order="descending"/>

      <xsl:variable name="currentId" select="@id" />
      <xsl:variable name="currentVotes" select="count($records//value [@key = $currentId])" />
      <xsl:variable name="currentPercentage" select="round (($currentVotes div $numberOfRecords) * 100)"/>
      
      <li>
          <xsl:value-of select="."/>
          <div class="scorebarcontainer" style="width:100%;background-color:#eee;height:20px"><span style="float:left;"><xsl:value-of select="$currentPercentage"/> %</span>
            <div class="scorebar" style="width:{$currentPercentage}%;background-color:#ccc;height:20px"></div>
        
        </div>
              </li>
   </xsl:for-each>
  </ul>
       </xsl:for-each>
    </div>

  
    </xsl:if>
</xsl:template>

</xsl:stylesheet>